Computer simulation for air-coupled ultrasonic testing

Abstract

Air-coupled ultrasound is used as non-contact ultrasonic testing method. For wider application of air-coupled ultrasonic technique, it is required to know situation of ultrasonic propagation between air and solid. Transmittance of the ultrasonic waves from air to solids is extremely small with 10-5 however it was revealed that, by using computer simulation methods based on the two-stage elastic wave equation in which two independent variables of stress and particle velocity are used, visualization calculation of ultrasonic propagation between air and solid was possible. In this report, the calculation of air-coupled ultrasound using the new Improved-FDM for computer simulation of ultrasonic propagation in solids is shown. Waveforms obtained by 1-dimensional calculation are discussed for principle and performance of the calculation. Visualization of ultrasonic incidence to cylindrical steel pipe is demonstrated as an example to show availability for ultrasonic testing. © Published under licence by IOP Publishing Ltd.